JPH0249349B2 - SETSUCHAKUZAIYOJUSHISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for (meth)acrylic adhesives, and more particularly, to a resin composition for two-component adhesives that has excellent high-temperature creep properties and tackiness and has a long pot life. It is extremely suitable for use in hot melt type pressure sensitive adhesives. Conventionally, resin compositions consisting of an acrylic resin and a polyisocyanate as a crosslinking agent have often been used as liquid pressure-sensitive adhesives. However, the above-mentioned liquid acrylic pressure-sensitive adhesive using polyisocyanate as a crosslinking agent has a major drawback in that it cannot maintain a balance between pot life and high-temperature creep properties. In other words, with conventional acrylic liquid pressure-sensitive adhesives, if you try to improve high-temperature creep properties with a short heat treatment, the pot life becomes too short; Unless a special treatment such as heat treatment is carried out, the high temperature creep property is significantly reduced, and it has been difficult to obtain a liquid type pressure sensitive adhesive that satisfies both of these requirements at the same time. The two-component adhesive resin composition of the present invention solves the above-mentioned drawbacks of the prior art, and therefore has a long pot life and excellent high-temperature creep properties with an extremely short heat treatment time. It has excellent performance. On the other hand, rubbers such as styrene-isoprene or butadiene block copolymers have traditionally been used in hot melt type pressure sensitive adhesives. However, hot-melt pressure-sensitive adhesives using rubber have disadvantages such as poor high-temperature creep properties and relatively high application temperatures, so they are used in packaging tapes, masking tapes, adhesive sheets for wallpaper, etc. It was low grade and could only be applied to products that had a heat-resistant base material. The two-component adhesive resin composition of the present invention solves all of the above-mentioned drawbacks of conventional hot-melt pressure-sensitive adhesives, and has excellent high-temperature creep properties and relatively low application temperatures. It also has excellent characteristics. The resin composition for adhesives of the present invention has the following formula: (A) Formula (1) In the formula, R ₁ is H or methyl, preferably methyl,
R ₂ and R ₃ are each independently H or 1 to 1 carbon atom;
4 alkyl group, preferably an alkyl group having 1 to 2 carbon atoms, and n is 1 to 4, preferably 2 to 2.
Copolymerized monomer and/or formula () with an integer of 3 In the formula, R ₄ is H or methyl, preferably H, R ₅ and R ₆ are each independently H, a hydroxymethyl group,
A (meth)acrylic copolymer containing 0.2 to 30% by weight of a comonomer whose alkyl moiety represents an alkoxymethyl group having 1 to 4 carbon atoms, preferably H or a hydroxymethyl group; B) Formula Hal―CH ₂ ―R―CH ₂ ―Hal () where R is

[Formula] group or (-CH ₂ )- _n , preferably

[Formula], Hal represents Cl, Br or I, preferably Cl or Br, and m is an integer of 0 to 10, preferably 2 to 8; in acrylic copolymer

[Formula] Group or

【formula】 basis or

[Formula] Group and

[Formula] A resin composition for an adhesive, characterized in that Hal in the difunctional compound is 0.1 to 3 equivalents per total group. Examples of copolymerized monomers of formula () include N, N-
Diethylaminoethyl acrylate, N,N-dimethylaminoethyl acrylate, N-methylaminoethyl acrylate, N-ethylaminoethyl acrylate, N-tertbutylaminoethyl acrylate, N,N-dimethylaminopropyl acrylate, aminoethyl acrylate, N, N-
Diethylaminoethyl methacrylate, N,N
-Diethylaminoethyl methacrylate, N-
Examples include methylaminoethyl methacrylate, N-ethylaminoethyl methacrylate, N-tertethylaminoethyl methacrylate, N,N-dimethylaminopropyl methacrylate, aminoethyl methacrylate, N,N-dimethylaminoethyl methacrylate, etc. . Among them, N,
N-dimethylaminoethylmethacrylamide is preferred. On the other hand, as examples of the copolymerized monomer of formula (), acrylamide, methacrylamide, N-methylolacrylamide, and N-methylolmethacrylamide are preferable, and acrylamide and N-methylolacrylamide are preferable. The (meth)acrylic copolymer used in the adhesive resin composition of the present invention is a copolymer of the above formula () and/or a (meth)acrylic copolymer of the above formula (). 0.2-30% by weight per system copolymer,
Preferably it is contained in an amount of 1 to 10% by weight. and expression()
0.2 to 30% by weight, preferably 1
A (meth)acrylic copolymer containing up to 10% by weight is particularly suitable. As used herein, the term "(meth)acrylic copolymer" refers to a copolymer in which one or more types of acrylic alkyl ester and/or methacrylic acid alkyl ester account for 50% by weight or more per copolymer. It is something. The content of these acrylic alkyl esters and/or methacrylic esters is preferably 65% by weight or more, most preferably 85% by weight or more, based on the copolymer. Such acrylic acid alkyl esters and methacrylic acid alkyl esters include acrylic esters or methacrylic esters having an alkyl group having 1 to 18 carbon atoms, such as methyl, ethyl, butyl acrylate,
iso-butyl, t-butyl, 2-ethylhexyl,
octyl, lauryl, tridecyl, stearyl,
cyclohexyl, methyl methacrylate, ethyl, propyl, butyl, iso-butyl, t-butyl, 2-ethylhexyl, octyl, lauryl, stearyl, cyclohexyl, etc. The (meth)acrylic copolymer used in the present invention includes the above-mentioned acrylic acid alkyl ester, methacrylic acid alkyl ester, formula ()
In addition to the copolymerized monomer of formula (2) and/or the copolymerized monomer of formula (2), other copolymerized monomers may be contained as necessary. Examples of such comonomers include acrylonitrile, styrene, pinyltoluene, itaconic acid mono- or diester,
Examples include fumaric acid mono- or dialkyl ester, methacrylonitrile, allyl alcohol, vinyl acetate, vinyl chloride, vinylidene chloride and the like. The (meth)acrylic copolymer used in the present invention has a number average molecular weight (hereinafter referred to as M _N ) of 4000 to
500,000, preferably 10,000 to 200,000. If it is less than 4,000, the crosslinking density becomes too high and a tough coating cannot be obtained, while if it exceeds 500,000, the viscosity increases too much when used as a liquid pressure-sensitive adhesive, which is not preferable. Further, when used in a hot melt type pressure sensitive adhesive, it is particularly preferably 10,000 to 100,000. The term "liquid pressure-sensitive adhesive" as used herein refers to a type of pressure-sensitive adhesive in which the main adhesive component is dissolved or dispersed in a liquid such as an organic solvent or/and water. Examples of conventional liquid pressure-sensitive adhesives include two-component pressure-sensitive adhesives consisting of an acrylic resin solution (organic solvent-based) and a polyisocyanate crosslinking agent, and acrylic resin solutions. There are two-component pressure-sensitive adhesives consisting of an emulsion (aqueous) and an acid component. R of the bifunctional compound of formula () used in the adhesive resin composition of the present invention is

Examples in the case of [Formula] include p-xylylene dichloride, o-xylylene dichloride, m-xylylene dichloride, p-xylylene dibromide, o-xylylene dibromide, m-xylylene dibromide,
These include p-xylylene diiodide, o-xylylene diiodide, m-xylylene diiodide, etc. In addition, examples when R is (-CH ₂ ) _-n include α,ω-dichloropropane, α,ω-dichlorobutane, α,ω-dichloropentane, α,ω-
Dichlorhexane, α,ω-dichlorheptane,
α,ω-dichlorooctane, α,ω-dichlorononane, α,ω-dichlorodecane, α,ω-dibromopropane, α,ω-dibromobutane, α,ω-
Dibromopentane, α,ω dibromohexane,
Examples include α,ω-dibromooctane, α,ω-dibromononane, and α,ω-dibromodecane. Among the bifunctional compounds of the above formula (), R is

[Formula] is preferred, and p-xylylene dichloride and p-xylylene dibromide are particularly preferred. The above-mentioned bifunctional compound is the above-mentioned (meth)acrylic copolymer.

[Formula] Group or

[Formula] Group or (

[Formula] Group +

0.1 to 3 equivalents, preferably 0.5 to 2 equivalents, most preferably 0.9 to 1.1 equivalents per [Formula] group)
Equivalent amounts are used. If the amount is less than 0.1 equivalent, the high-temperature creep property will deteriorate, which is undesirable, while if it exceeds 3 equivalents, the pressure sensitivity will decrease, which is not preferred. The (meth)acrylic copolymer of the present invention can be produced by a solution polymerization method, a dispersion polymerization method, a bulk polymerization method, or the like, which are commonly used in the production of acrylic polymers. The solutions, dispersions, or semi-solids of the (meth)acrylic copolymer thus obtained are suitably used in the resin composition for adhesives of the present invention; Solutions or dispersions, preferably solutions, are used; for hot melt pressure sensitive adhesives, semisolids or dried products from solutions are used. The resin composition for adhesives of the present invention mainly contains a (meth)acrylic copolymer and a bifunctional compound, but if necessary, a phenol resin,
Natural resins, petroleum resins, coumaron-indene resins, rosin esters, hydrated rosin resin derivatives, and other known additives such as tackifiers, antioxidants, ultraviolet absorbers, plasticizers, and pigments are added to (meth)acrylic resins. It can be used by blending it into a copolymer. The resin composition for adhesives of the present invention is a two-component adhesive consisting of two components, a (meth)acrylic copolymer and a bifunctional compound, as described above. If a liquid-type pressure-sensitive adhesive is required, it can be obtained by weighing a predetermined amount of the above two components, heating the mixture to 60°C if necessary at room temperature in a suitable open container, and mixing the two components. It will be done. The liquid pressure-sensitive adhesive obtained in this way has an extremely long pot life.
For example, it does not gel even if left at room temperature for 4 days, and has excellent high-temperature creep properties (e.g. 25 x 25 mm) when a liquid adhesive is applied and dried at 100°C for 2 minutes, then pressure-bonded to the adherend. 1Kg load per adhesive area at 100℃
No creep occurred at all for over 120 minutes). It is not necessarily clear why the resin composition for adhesives of the present invention has excellent high-temperature creep properties in an extremely short heat drying time despite its long pot life. Meta)
acrylic resin

[Formula] or

Although the bond between [Formula] and the halogen of the bifunctional compound is difficult to proceed due to the presence of the solvent, it is presumed that the bond proceeds quickly when the solvent dries. . When a hot-melt pressure-sensitive adhesive is required, a predetermined amount of semi-solid (meth)acrylic polymer is heated to a temperature that allows stirring, and a predetermined amount of a bifunctional compound is added thereto and mixed uniformly. obtain a melt. The melt thus obtained has a low melt viscosity, so it can be coated even at a relatively low temperature, for example, 100° C., and has excellent high-temperature creep properties after pressure bonding. The reason why the hot-melt pressure-sensitive adhesive of the present invention has the excellent feature of being able to be applied at a relatively low temperature is that the adhesive composition of the present invention has good tackiness and also has good high-temperature creep properties. It is presumed that this is because it has become possible to use a (meth)acrylic copolymer with a relatively low degree of polymerization. By the way, with conventional acrylic polymer and isocyanate adhesives, improving the tackiness reduces the high-temperature creep property, and improving the high-temperature creep property reduces the tackiness. Adhesives based on mixtures have not been put into practical use as hot melt pressure sensitive adhesives. The present invention will be specifically explained below by carrying out the invention.
The numbers of parts and percentages shown below are by weight unless otherwise specified. Example 1 (a) 100 parts of n-heptane and 0.1 part of azobisisobutyronitrile were placed in a reactor equipped with a reflux condenser and a stirrer, and after raising the temperature to a reflux state, 190 parts of octyl acrylate and dimethyl were added. A mixture with 10 parts of aminoethyl methacrylate was added dropwise over 90 minutes, and the reaction was continued under reflux for 60 minutes. Furthermore, a solution of 5 parts of toluene and 1.5 parts of azobisisobutyronitrile was added dropwise over 180 minutes, and the reaction was continued for 60 minutes. Thereafter, the mixture was further heated, the reflux liquid was taken out, and 50 parts of the solvent was distilled off. The obtained resin liquid had a solid content of 66%, a number average molecular weight of the resin component of 20,000, and was a fluid solution with coatability. A mixture of 100 parts of this resin liquid and 2 parts of p-xylylene dichloride is 48
It had a pot life of more than 1 hour. Apply this mixture to a 25μ polyester film to form a dry coating.
Coat it to a thickness of 40μ and dry it for 2 minutes at 100℃.
After leaving it for a while, it was pasted on a stainless steel plate and its adhesive performance was measured, and the results were as shown in Table 1. (b) Further, the obtained resin liquid is evaporated to dryness to give a highly fluid melted liquid of 48000 cps at 100°C, and the above-mentioned p-xylylene chloride is added to this and applied. It was also possible to provide a pressure-sensitive adhesive sheet. In this case, coating was possible even at 90°C, and the creep resistance was over 120 minutes. Comparative Example 1 Using the same polymerization apparatus as in Example 1, the same operation was performed using 2-hydroxyethyl methacrylate instead of dimethylaminoethyl methacrylate to obtain a resin liquid with a solid content of 65% and exhibiting coatable fluidity. Ta. When 8 parts of Coronate L (a polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd.) was added to 100 parts of this resin solution, the viscosity of the mixed solution began to increase, and after 4 hours, it gelled and no longer exhibited fluidity. An adhesive tape was prepared in the same manner as in Example 1 using the resin liquid immediately after mixing, and the adhesive properties were measured. Table 1 shows the results. Example 2 Polymerization was carried out in the same manner as in Example 1, using diethylaminoethyl methacrylate in place of dimethylaminoethyl methacrylate, to obtain a resin liquid having a solid content of 66% and exhibiting coatable fluidity. This resin liquid
A mixture of 100 parts and 3 parts of p-xylylene dibromide had a pot life of 48 hours or more at room temperature. This mixed solution was applied to coated paper so that the dry film thickness was 40μ, left at room temperature for 72 hours, and then attached to a stainless steel plate.The heat resistance was investigated in the same manner as in Example 1. It showed holding power. Example 3 In the same polymerization apparatus as in Example 1, 150 parts of 2-ethylhexyl acrylate, 45 parts of vinyl acetate, 5 parts of acrylamide, and 60 parts of ethyl acetate were added, dry nitrogen was introduced, and after stirring at room temperature for 30 minutes, azobisisomer was added. Add 0.2 parts of butyronitrile, gradually raise the temperature until the content reaches 65°C, then add 540 parts of ethyl acetate over 2 hours, react at 65°C for another 1 hour, and then raise the temperature to reflux. The reaction was continued for hours to obtain a resin liquid with a solid content of 32%. A mixed solution prepared by adding 0.2 parts of α,ω dichlorobutane to 100 parts of this resin liquid was stable even when left at room temperature for more than one week. This mixture was applied to a 25μ polyester film so that the dry film thickness was 30μ, dried at 100℃ for 2 minutes, pasted with release paper, left at 100℃ for another 30 minutes, and then pasted on a stainless steel plate. As a result of examining creep resistance in the same manner as in Example 1, it showed a holding power of 2 hours or more at 100°C. The results are shown in Table-1. Comparative Example 2 An adhesive sheet was made in the same manner as in Example 3 without adding α,ω dichlorobutane using the same resin liquid as in Example 3, and the heat-resistant adhesiveness was examined.
The deviation occurred within 30 minutes. Comparative Example 3 Coronate L1 was added to 100 parts of the same resin solution as in Example 3.
An adhesive tape was prepared in the same manner as in Example 1 using the mixed solution obtained by adding 50% of the mixture, and the adhesive properties were measured. Table 1 shows the results. Note that this mixed solution turned into a gel after 12 hours and could no longer be applied.

【table】

Claims (1)

[Claims] 1 (A) Formula () In the formula, R ₁ is H or methyl, R ₂ and R ₃ each independently represent H or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 4. or expression() In the formula, R ₄ is H or methyl, R ₅ and R ₆ are each independently H, a hydroxymethyl group, or an alkoxymethyl group having 1 to 4 carbon atoms in the alkyl moiety. A (meth)acrylic copolymer containing 30% by weight and (B) formula () Hal-CH ₂ -R-CH ₂ -Hal () in which R is [formula] group or (-CH ₂ )- _n represents Cl, Br, or I, and m is an integer from 0 to 10. A resin composition for adhesives, characterized in that Hal in the bifunctional compound is 0.1 to 3 equivalents per group and/or group [Formula]. 2 The copolymerized monomer has the formula () The composition according to claim 1, wherein R ₁ , R ₂ , R ₃ and n are copolymerized monomers having the above meanings. 3 Bifunctional compounds The composition according to claim 1 or 2, which is 4 The copolymerized monomer is The composition according to any one of claims 1 to 3. 5. The adhesive resin composition according to any one of claims 1 to 4, which is used in a liquid pressure-sensitive adhesive. 6. The adhesive resin composition according to any one of claims 1 to 4, which is used in a hot-melt pressure-sensitive adhesive.